CO2 and CO2e.
The IPCC reports 40 years of anthropogenic CO2 together with anthropogenic methane CO2e for the 40-year period, 1970-2010 in their report, “Summary for Policymakers.”
There is no evidence that climate policies deployed during this time period have had any effect to turn down the upward CO2e trend line that continues today. For convenience, Figure SPM.1 is repeated here.
The lengthy caption for this figure states the basis for the data as depicted. “Emissions are converted into CO2-equivalents based on GWP100 from the IPCC Second Assessment Report.”
GWP Ref: https://ghginstitute.org/2010/06/28/what-is-a-global-warming-potential/
The trend in quantifying 20-year methane global warming properties is depicted in terms of step increases. Changes are due to advances in atmospheric science.
We see that GWP100 from 1996 was GWP100 = 21. We would agree with employing GWP100 assuming we have all century to contain CO2e, but we don’t. Relying on the IPCC AR5 standard for GWP20 to modify Figure SPM-1, a depiction of the near-term effects of methane involves adjusting the blue methane bar by … GWP100/GWP20 = 84/21 = 4x. Such a depiction by IPCC or any other source has not been found.
The last biggest mistake. Consequently the blue methane bar reported in SPM.1 is only one-fourth its true height. A pasted-up correction to figure SPM.1 is given in the following graphic and depicts the impact of the current near-term GWP20 standard regarding the root cause of climate change.
Who knew that for the last 50 years anthropogenic CO2 has actually been second to the real driver of climate change, CH4. Due diligence suggests that the attainment of Oregon climate goals must accurately account for the astounding impact of CH4 in Oregon.
Full disclosure: we are unable to locate other reports correlating the conclusion that anthropogenic CH4 emissions exceed fossil fuel and industrial CO2 emissions.
Measurements. Atmospheric CO2 has been and continues to be measured, plots are readily accessible, and they show no signs of decline, ever. http://scrippsco2.ucsd.edu/history_legacy/keeling_curve_lessons
Nevertheless it is reassuring to know that CO2 is absorbed and recycled as O2 in natural carbon sinks. The US West Coast forests from California to Southern Alaska are regarded as the densest carbon sink on the planet.
Neither are the measurements of CH4 in Earth’s atmosphere in decline. http://www.scientificamerican.com/article/debate-rises-over-real-source-of-higher-methane-emissions/
Natural gas industry owners and operators do not report measured methane leaks and releases, and instead are allowed by government agencies such as the US EPA to provide mere estimates. We are still looking for a massive CH4 sink like forests are for CO2. For all these reasons CH4 deserves immediate and imperative attention. The suggestion that Oregon natural gas distributors MUST obtain accurate data characterizing the upstream methane leaks and releases as a condition for accepting commodity deliveries seems obvious but is not current practice. How can the worst carbon pollution source be allowed to continue UNMEASURED AND UN-REPORTED. This does nothing for Oregon GHG Inventory accuracy. Oregon licensed distributors serving the public can require this of their suppliers. Without actual data, Oregon’s critical reports and due diligence in decisions involving goal attainment are not credible or effective.
Such fugitive methane reporting need not remain optional. Rulemaking to implement the intention of SB 1547B could levy this practice as a requirement, with no cost to Oregon or Oregon energy distributors. The costs to gas developers and logistics suppliers are already baked in as part of the cost of doing proper business. Not Oregon’s problem. Can they be heard to claim safe operations with no methane data to be reported? With methane destroying the place? Oregon distributors and ratepayers carry the price burden of lost upstream commodity, so we deserve to know.
How can we be held responsible, in the future as the social cost of carbon (SCC) becomes a serious issue, for the social cost of escaped CH4? The numbers are impressive. A modest SCC for CO2 is $40/ton. With the GWP20 factor of 84 for CH4, we get 84x$40/ton = $3360/ton. Unless I missed something, that could leave a mark.